Flashing-Induced Density Wave Oscillations in a Boiling Natural Circulation System

2012 ◽  
pp. 280-299
Author(s):  
Masahiro Furuya
Keyword(s):  
Natural Circulation ◽  
Density Wave ◽  
Circulation System ◽  
Density Wave Oscillations

Flow Stability of Heat Recovery Steam Generators

2004 ◽  
Vol 128 (4) ◽  
pp. 840-848 ◽  
Author(s):  
Heimo Walter ◽  
Wladimir Linzer
Keyword(s):  
Heat Recovery ◽  
Flow Instability ◽  
Natural Circulation ◽  
Density Wave ◽  
Horizontal Tube ◽  
Flow Stability ◽  
Steam Generators ◽  
Tube Bank ◽  
Density Wave Oscillations ◽  
Initial Results

This paper presents the results of theoretical flow stability analyses of two different types of natural circulation heat recovery steam generators (HRSG)—a two-drum steam generator—and a HRSG with a horizontal tube bank. The investigation shows the influence of the boiler geometry on the flow stability of the steam generators. For the two-drum boiler, the steady-state instability, namely, a reversed flow, is analyzed. Initial results of the investigation for the HRSG with a horizontal tube bank are also presented. In this case, the dynamic flow instability of density wave oscillations is analyzed.

Correlations for the Determination of the Inception Conditions of Density-Wave Oscillations for Forced and Natural Circulation Steam Generator Tubes

1980 ◽  
Vol 102 (1) ◽  
pp. 14-19 ◽  
Author(s):  
H. C. U¨nal
Keyword(s):  
Steam Generator ◽  
Mass Velocity ◽  
Natural Circulation ◽  
Density Wave ◽  
Steam Quality ◽  
Forced Circulation ◽  
Percent Accuracy ◽  
Steam Generator Tubes ◽  
Density Wave Oscillations ◽  
Heated Length

Accurate and simple correlations are presented to determine the inception conditions of density-wave oscillations in steam generator tubes. The correlations predict the power at the start of the density-wave oscillations within about 6.5 percent accuracy for long (i.e., L ≥ 10 m) forced circulation steam generator tubes and within about 20 percent accuracy for natural circulation and short forced circulation steam generator tubes. The ranges of the operating conditions and geometries for the data used to establish the correlations are as follows: Forced circulation tubes: Geometry: circular-straight tubes and serpentines, a circular coil and a rectangular straight tube; type of heating: electrical or sodium heating; the ratio of the heated length to diameter: 153–9502; pressure: 4.1–17.3 MN/m2; outlet steam quality: 0.27–1.85; inlet subcooling: 2.8–245.9 K; mass velocity: 118–2088 kg/m2s. Natural circulation tubes: Geometry and heating conditions: electrically heated circular tubes and annuli; ratio of the heated length to diameter: 34–489; pressure: 0.2–7.1 MN/m2; outlet steam quality: 0.04–0.62; inlet subcooling: 0–244 K; mass velocity: 529–1230 kg/m2s. The number of data considered is 106 for forced circulation tubes and 110 for natural circulation tubes.

Validation of TRACE Code for Flashing-Induced Density Wave Oscillations in SIRIUS-N Facility, Which Simulates ESBWR

2012 ◽  
Author(s):  
Masahiro Furuya ◽  
Yoshihisa Nishi ◽  
Nobuyuki Ueda
Keyword(s):  
Heat Flux ◽  
Natural Circulation ◽  
Stability Boundary ◽  
Oscillation Amplitude ◽  
Density Wave ◽  
Stability Limit ◽  
Type I ◽  
Wave Oscillation ◽  
System Pressure ◽  
Density Wave Oscillations

The TRACE code was validated against the flashing-induced density wave oscillation in the SIRIUS-N facility at low pressure (from 0.1 to 0.5 MPa) as a part of the international CAMP-Program of USNRC. The SIRIUS-N facility is a scaled copy of natural circulation BWR (ESBWR). Stability map of TRACE agrees with that of SIRIUS-N facility at low subcooling region, though instability observed in the lower heat flux and higher subcooling region from the stability limit of experiment. The TRACE code demonstrates the flashing-induced density wave oscillation characteristics: The oscillation period correlates well with the transit time of single-phase liquid in the chimney regardless of the system pressure, inlet subcooling, and heat flux. Unlike Type-I and II density wave oscillations, the inlet or exit throttling does not affect stability boundary and oscillation amplitude of flashing-induced density wave oscillations significantly. Increasing pressure decreases oscillation amplitude. The comprehensive validation confirms that the TRACE code can demonstrate thermal-hydraulic stability of natural circulation BWRs.

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